Method of drawing hollow glass cylinders.



W1 L. MONRO. METHOD OF DRAWING HOLLOW GLASS CYLlNDERS.

APPLlCATlON FILED JULY 24, 1915.

Patented Feb. 25, 1919.

LQ95 SQSQ INVENTOR r ce WILLIAM L. MONRO, OF PITTSBURGH, PENNSYLVANIA, ASSIGNOR TO WIIVDOW GLASS MACHINE COMPANY, OF PITTSBURGH, PENNSYLVANIA, A CORPORATION OF NEW" mess mentor) or DRAWING HOLLOW GLASS "CYLINDERS.

messes.

Application filed m 24,

To all whom it may concern Be it known that I, WILLIAM L. Monro, a citizen of the United States, residing at Pittsburgh, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Methods of Drawing- Hollow Glass Cylinders, of which the following is a full, clear, and exact description, reference being had to the accompanying drawings, forming part of this specification, in which- Figures 1 and2 are vertical sections showing two different forms of baits embodying m invention. 4 My invention relates to the :method of drawing hollow glass cylinders by the use of cold baitsl By the term cold'bait as used herein and in the appended claims, I refer to a bait which may be either cool or somewhat heated, but which will in all cases be immersed in a glass bath in drawing at a temperature very considerably below that at which there .will be fusion between the moltenglass and the metal of the bait.

Prior to my invention, in the'use of baits of this character, it wassupposed that the anchorage groove or surface of the bait by means of which the novel is formed and the article supported during the draw, must have very little if any reverse inclination. It was thought that any reverse inclination of this surface so as to give it a pronounced form would cause breakage of the glass due to the different coeiiicientsof expansion of the glass and the metal or alloy of which the bait is composed. however, that such 18 not the case and that the baits may be provided with anchorage grooves whose inner wall is at any angle to the horizontal up to 90 or thereabout; and that such baits may be employed to advantage without any greater degree of breale age of the glass than with the forms heretofore used.

There is distinct advantage in the use of baits of the type provided by my invention, since the hook-form or" the anchorage gives a better and more positive grip of the glass and fewer cylinders are lost by slippage of the bait from the glass. y

In Fig. 1, I have shown a form of my invention in which the bait 2 is of the usual hollow. cylindrical form, of cast iron, or other suitable metal or alloy, with the threadedtconnection 3 for attachment to the Specification of Letters Patent.

drawer desires to form.

I have discovered,

1915, Serial No. 41,686.

Patented Fee. 25;, 1919.

usual air supply pipe for delivering air to the interior of the bait and to the article during drawing. The bait has a cylindrical openlng' l at its lower end which is surrounded by the annular anchorage or groove 5 whoseinner wall 6 projects backwardly within the interior of the bait at an angle of substantially 90 to the horizontal- Preferably the upper edge portion 7 of the flange 6 is somewhat rounded or convexed.

In Fig. I have shown the bait2f of generally similar form to that shown in Fig. 1,

but in which the inner I wall 6 of the to the glass will occur; the bait is then slowly raised in the usual manner. A slight amount of air may be admitted into the bait while the novel is being formed; but. the air supply may be controlled in any usual or suitable way, according to the shape of the cap portion of the article which the I have found thatyby the use of cold baits such as described, a glass novel will be formed in the bait groove by the chilling action of the metal, which will not pull out or slip during the drawing, and which is,

nevertheless, free of strains of a character to.

cause breakage.

I do not limit myself to the two particular forms of anchorage grooves which I. have herein described, as various forms of such grooves may be employed without de-' parting from the spirit and scope of my in.-

vention, as defined in the appended claims.

I-cIaimI. e e

1. In "the art of drawing hollow glass i cylinders, the method which consists in im-'.

mersifrg in the molten glass adioll w bait which .is of a temperature below; halt at;

which molten glass will fuse thereto and which has an internal grooved flange whose inner wall is" at an angle of at least 45 degrees to the horizontal, and holding the irebait inor adjacent to the molten glass for a suflicient period of time to cause the glass in said groove to chill therein to form a novel having a positive reverse hook engagement into the bait but which is not fused thereto, and then drawing the positive hook engagement between the glass and the bait acting to prevent any substantial radial shrinkage of the novel, substantially as described.

21 In the art of drawing hollow glass cylinders the method which consists in immersing in the molten glass a hollow bait which is of a temperature below that at which molten glass will fuse thereto and which has an internal grooved flange surrounding an unobstructed circular opening, the inner Wall'Of the said flange being at anangle of at least 45 degrees to the horizontal, and holding the bait in or adjacent to the molten glass for-a suflicient period of time to cause the glass in said groove.

to chill therein to form a novel having a positive reverse-hook engagement into the bait but which is not fused thereto, and

. then drawing, the positive'hook engagement between the glass and the bait acting to prevent any substantial radial shrinkage of the novel, substantially as described.

3. In the art of drawing hollow glass cylinders, the method which consists in immersing in the molten glass a hollow bait which is at a temperature below that at which molten glass will fuse thereto and which has a novel-supporting surface surrounding an unobstructed circular opening, the novel supporting surface having anchorage means, the anchorage surface of which is at an angle of more than 45 degrees to the horizontal and arranged to prevent radial shrinkage of the novel, and holding the bait in or adjacent to the molten glass fora sufiicient period of time to cause the glass in said groove to chill therein to form a novel having a positive reverse hook engagement into the bait but which is not fused thereto, and then drawing, the.positive hook engagement between the glass and the bait acting to prevent any substantial radial shrinkage of the novel, substan tially as described.

In testimony whereof I have hereunto set my hand.

WILLIAM L. Moulao.

Witnesses: I

ROBT. WHALEN, ALBERT L. swrr'r. 

